The alternator in a motor vehicle generates electricity. It charges the battery and powers the electrical items of the vehicle when the engine is running. Alternators are typically in most types of vehicles, including cars, trucks, motorcycles, and any other vehicles with engines. The alternator is characterized as an “engine accessory load” because it is driven by the engine, thus creating an added strain on the engine's operation. Alternators typically add a moderate accessory load, but the load may be higher with computer controlled cars, which are increasingly common today.
Other accessory loads include components that are connected to the fan belt, accessory belt or serpentine belt. Besides the alternator, these components often include the power steering pump, water pump, air conditioning compressor, and cooling fan. These components take power from the engine when they are running, and most of them are always running when the engine is running. Along with the torque needed by the engine for driving, it is preferable to account for the torque from these accessory load components when determining the engine torque.
Existing systems that account for alternator torque either set the alternator torque to a fixed value, and do not alter it during operation, leading to incorrect engine torque estimations, or approximate alternator torque using a calibration surface, such as a predetermined chart with alternator rotating speed and duty cycle as inputs.
Unfortunately, estimating errors in these types of systems frequently occur because the engine torque is not updated in real time. Therefore, there exists a need for a system that solves or at least alleviates some or all of these problems.